An improved cutter assembly for use with a header of an agricultural harvester is provided. The assembly includes a pair of oppositely directed knife blades or cutter bars and a center knife drive. A crank shaft drives both knife blades in linear reciprocating paths with no fore and aft movement. As a consequence, harmful fore and aft vibration is eliminated. The assembly is simple and durable in design, less susceptible to vibration-induced wear and tear, and comparatively simple to manufacture and repair.

A harvest header apparatus for harvesting a first crop in a field while preventing damage to a second later crop planted in the same field. A header table with a knife mounted along a lower front edge thereof has a plurality of crop shields attacked to and spaced along the header table at a selected shield spacing, each crop shield extending forward from a rear portion thereof located under the knife to a forward end thereof located forward of the knife. A forward portion of each crop shield slopes upward such that crop plants contacted by the forward portion of each crop shield are pushed downward and pass under the knife without contacting the knife. The shield spacing is selected so the crop shields move along rows of second crop and push the second crop plants down and under the table such that same are not contacted by the knife.

The pivoting action sickle drive has a low profile allowing incorporation in or below a floor of a header of a plant cutting machine to allow passage of cut plant material thereabout. The drive includes a substantially flat rotatable input element, and a drive arm connected eccentric thereto for eccentric rotation along an epicyclical path. The arm extends to a connection with a pivot arm of a pivot element that connects to a knife arm that drives a sickle knife assembly, such that the pivot element, knife arm and knife assembly will be reciprocatingly driven by the eccentric rotation of the drive arm. A second drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will cancel. The drives can be packaged in a forwardly tapered or curved enclosure, and the pivot elements can be correspondingly shaped to streamline the drives.

The pivoting action sickle drive has a low profile allowing incorporation in or below a floor of a header of a plant cutting machine to allow passage of cut plant material thereabout. The drive includes a substantially flat rotatable input element, and a drive arm connected eccentric thereto for eccentric rotation along an epicyclical path. The arm extends to a connection with a pivot arm of a pivot element that connects to a knife arm that drives a sickle knife assembly, such that the pivot element, knife arm and knife assembly will be reciprocatingly driven by the eccentric rotation of the drive arm. A second drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will cancel. The drives can be packaged in a forwardly tapered or curved enclosure, and the pivot elements can be correspondingly shaped to streamline the drives.

A crop header having a frame mounted on a vehicle has a sickle cutter bar and a draper. The draper is guided at its front edge by a longitudinally extending rail mounted on the frame. The cutter bar is mounted at spaced positions by spring blades attached to a fixed beam at the rear which allow up and down flexing movement of the cutter bar relative to the draper rail. At the center discharge the cutter bar is carried on shorter blades which are carried on a beam in front of the front draper roller. A locking device is provided for commonly and automatically moving the beam in a direction to lift the cutter bar into a raised position in which the cutter bar is locked against flexing movement with the locking device being operable in response to the cutter bar being raised off the ground.

A method for operating a permanently excited synchronous motor of a hand-held working device includes the steps of: sensorlessly determining a position variable representative of a position of a rotor of the synchronous motor at a standstill; determining a direction variable for a continuous rotation of the rotor from standstill in a direction on the basis of the determined position variable such that an absolute value of an attainable torque that can be generated by the synchronous motor during its sensorless actuation for the rotation in the direction is greater than an absolute value of a breakaway torque limit of the working device; and sensorlessly actuating the synchronous motor on the basis of the determined direction variable for the rotation in the direction.

A crop header having a frame mounted on a vehicle has a sickle cutter bar and a draper. The draper is guided at its front edge by a longitudinally extending rail mounted on the frame. The cutter bar is mounted at spaced positions by spring blades attached to a fixed beam at the rear which allow up and down flexing movement of the cutter bar relative to the draper rail. At the center discharge the cutter bar is carried on shorter blades which are carried on a beam in front of the front draper roller. A locking device is provided for commonly and automatically moving the beam in a direction to lift the cutter bar into a raised position in which the cutter bar is locked against flexing movement with the locking device being operable in response to the cutter bar being raised off the ground.

The pivoting action sickle drive has a low profile allowing incorporation in or below a floor of a header of a plant cutting machine to allow passage of cut plant material thereabout. The drive includes a substantially flat rotatable input element, and a drive arm connected eccentric thereto for eccentric rotation along an epicyclical path. The arm extends to a connection with a pivot arm of a pivot element that connects to a knife arm that drives a sickle knife assembly, such that the pivot element, knife arm and knife assembly will be reciprocatingly driven by the eccentric rotation of the drive arm. A second drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will cancel. The drives can be packaged in a forwardly tapered or curved enclosure, and the pivot elements can be correspondingly shaped to streamline the drives.

The pivoting action sickle drive has a low profile allowing incorporation in or below a floor of a header of a plant cutting machine to allow passage of cut plant material thereabout. The drive includes a substantially flat rotatable input element, and a drive arm connected eccentric thereto for eccentric rotation along an epicyclical path. The arm extends to a connection with a pivot arm of a pivot element that connects to a knife arm that drives a sickle knife assembly, such that the pivot element, knife arm and knife assembly will be reciprocatingly driven by the eccentric rotation of the drive arm. A second drive can oppositely drive a second sickle knife assembly, such that opposite forces generated by the drives will cancel. The drives can be packaged in a forwardly tapered or curved enclosure, and the pivot elements can be correspondingly shaped to streamline the drives.

An agricultural vehicle includes a chassis and a header carried by the chassis. The header includes: a frame coupled to the chassis; a cutter bar assembly connected to the frame; a plurality of linkage arms connected to the cutter bar assembly; and a plurality of sacrificial connectors each connected to a respective one of the linkage arms and the frame, each of the plurality of sacrificial connectors including at least one sacrificial region configured to deform or shatter upon an overload force acting on the respectively connected linkage arm.